Changes in the subcellular distribution of free carnitine and its acyl derivatives in diabetic rat hearts following treatment with L-carnitine

Carnitine deficiency has been demonstrated in diabetic hearts, and it is also well known that L-carnitine administration has a beneficial effect on cardiac function. Carnitine treatment would be expected to reduce the accumulation of long-chain acylcarnitine. However, many reports have shown that myocardial long-chain acylcarnitine levels were increased following treatment with L-carnitine in whole-heart studies. Since acylcarnitine exists in both the mitochondrial and cytosolic compartments, it is difficult to investigate changes in subcellular distribution by studying whole-heart preparations. The present study investigated the myocardial subcellular distribution of carnitine and its acyl derivatives in diabetic rats with or without L-carnitine treatment. Approximately 90% of total cellular carnitine was located in the cytosol in the diabetic hearts. Both mitochondrial and cytosolic levels of free carnitine and short-chain acylcarnitine were significantly decreased in the diabetic heart. However, the mitochondrial level of long-chain acylcarnitine was significantly increased. L-carnitine treatment reduced the mitochondrial level of long-chain acylcarnitine, but the cytosolic level of long-chain acylcarnitine was significantly increased. These results show that L-carnitine treatment prevents the accumulation of long-chain acylcarnitine in the mitochondrial space and then reduces the detergent effect of long-chain acylcarnitine on the mitochondrial membrane. We suggest that it is a possible mechanism of the beneficial effect of L-carnitine treatment on the diabetic heart.

Clinical course and outcome of idiopathic membranous nephropathy in Japanese children

We retrospectively studied 12 Japanese children (8 boys, 4 girls) with idiopathic membranous nephropathy (IMN), aged 2.9-15.8 (mean 7.7) years at onset. All patients were identified through either screening or a routine urinalysis; proteinuria was present in all, haematuria, which was macroscopic in 4, in 11. Three had nephrotic syndrome (NS) at or soon after onset. Stages on electron microscopy, performed in 10 patients, were I in 3, II in 5 and III in 2. Steroids alone or with cyclophosphamide were administered to 5 patients, including the 3 patients showing NS. Complete remission of proteinuria occurred in 8 patients 0.3-1.6 (mean 0.6) years after onset, and proteinuria did not recur. After a follow-up of 1.6-11.6 (mean 5.9) years, these 8 patients were in complete remission and the remaining 4 had only mild proteinuria; none had hypertension or impaired renal function. Thus, we infer that IMN in Japanese children may have a better course and outcome than IMN in non-Japanese children. Based on a comparative study of Japanese (previously reported cases added to ours) and non-Japanese (mostly Caucasian) children with IMN, this was confirmed; it is possible that steroid therapy in Japanese patients is more effective in inducing remission of NS and preserving renal function.

[Rapid alteration in serum lipoprotein profile after bile drainage in a patient with acute bile duct obstruction: contribution of cholestasis to cholesteryl ester-dominant ApoE-rich HDL accumulation]

Remarkably increased cholesteryl ester-dominant apoE-rich HDL with alpha 2-mobility, similar to the apoE-rich HDL observed in primary biliary cirrhosis, was found in a patient with acute bile duct obstruction due to common bile duct carcinoma. Bile drainage rapidly lowered her serum apoE-rich HDL from 34.1 to 6.1 mg/dl and from 96 to 10 mg/dl in terms of apoE (control; 2.6 +/- 1.5 mg/dl, n = 38) and of cholesterol (control; 6.7 +/- 2.3 mg/dl, n = 38), respectively. Disturbance in hepatic lipoprotein clearance due to the presence of cholestasis without severe liver damage is a possible cause of accumulation of cholesteryl ester-dominant apoE-rich HDL. Hence, plasma cholesteryl ester-dominant apoE-rich HDL level is supposed to be a good indicator of hepatic lipoprotein clearance. The measurement of this lipoprotein and the analysis of its lipid composition, by our convenient method, would be useful for the diagnosis of cholestasis and for the evaluation of hepatic function in cholestatic patients.

Further NMR-spectroscopic studies of interaction of phospholipid liposomes with methacryloyloxydecyl dihydrogen phosphate (MDP) in dental adhesives

To determine how MDP interacts with liposomes, the chemical shifts of dipalmitoylphosphatidylcholine (DPPC)/MDP and dilauroylphosphatidylethanolamine (DLEA)/cholesterol (CS)/MDP liposomes were studied by NMR spectroscopy using a D2O buffer solution at pH 7.0 as a model for biological membranes. Proton chemical shifts of MDP enhanced shielding in DPPC liposomes together with an increase in the mobility of DPPC. However, MDP signals were not observed in DLEA/CS liposomes due to saturation. It is known that an ionized chemical does not lead to increased permeability of cell membranes composed of a lipid bilayer. However, MDP, which is ionized at pH 7.0, had a large interaction with the liposome systems. This appeared to arise from hydrophobic interaction between deca methylene groups of MDP and acyl chains of phospholipid.

Increased plasma apolipoprotein E-rich high-density lipoprotein and its effect on serum high-density lipoprotein cholesterol determination in patients with familial hyperalphalipoproteinemia due to cholesteryl ester transfer activity deficiency

Plasma apo E-rich HDL was studied in regard to its quantity and chemical composition in the members of a family with cholesteryl ester transfer activity deficiency, exhibiting familial hyperalphalipoproteinemia. The approach involved a simple precipitation method established in our laboratory. Serum apo E-rich HDL concentrations for two homozygous members were elevated up to 66 and 60 mg/dl in terms of cholesterol (normal, 6.7 +/- 2.3 mg/dl, n = 38), and to 9.4 and 10.8 mg/dl in terms of apo E (normal, 2.6 +/- 1.5 mg/dl, n = 38). The cholesterol/apo E ratio (mole/mole) of apo E-rich HDL was higher in two homozygotes (669 and 531) than in two cholestatic patients with elevated apo E-rich HDL (268 and 149) and in normal subjects (242 +/- 115, n = 38). Chromatographic studies of the serum from a homozygote showed enlargement of all HDL subclasses and apo E in the larger HDL subclass. These facts indicate that the increase of apo E-rich HDL in this disease occurs secondarily to the enlargement of HDL particles, which require substances to cover their cores, having expanded due to the accumulation of cholesteryl ester. The sera from the homozygotes gave HDL cholesterol concentrations which were remarkably discrepant among commercial precipitating reagents, because of the difference in recovery of apo E-rich HDL with these reagents.

[Polycythemia vera terminating in chronic neutrophilic leukemia: studies on in vitro growth of hematopoietic progenitor cells]

A 57-year-old man, diagnosed as Polycythemia vera (PV), had been treated with administrations of Busulfan since 1984. Three years later, the number of neutrophils in peripheral blood increased to 50,000/microliters with progression of splenomegaly, and the case was diagnosed as Chronic neutrophilic leukemia (CNL) based on the criteria by Miura et al, in November, 1989. In spite of 6MP and Busulfan therapy, marked neutrophilia and splenomegaly progressed, and the patient died due to liver dysfunction in June of 1991. To clarify the pathophysiology of PV and CNL, we studied the in vitro growth kinetics of hematopoietic progenitor cells in bone marrow of this unique case and made a comparison with those of 4 cases of PV and 4 normal volunteers employing methylcellulose culture. As in other cases of PV, erythroid colonies were formed in culture of bone marrow from this patient without addition of erythropoietin. Furthermore, spontaneous colonies derived from CFU-GM and CFU-Mix increased remarkably in this case only. The results suggest that the hematopoietic abnormalities in this case involve the multipotent stem cells as well as erythroid and granuloid-macrophage progenitors.

Effect of L-carnitine on the cellular distribution of carnitine and its acyl derivatives in the ischemic heart

The purpose of this study was to investigate the cellular distribution of carnitine and its acyl derivatives in the normal and ischemic myocardium, and the effects of exogenous 1-carnitine on this distribution and mitochondrial function in the ischemic dog heart. Under non-ischemic conditions, about 93% of the total cellular carnitine was located in the cytosolic compartment and 6.5% in the mitochondrial compartment. Sixty minutes of ischemia induced a decrease in the cytosolic free carnitine content, but caused the accumulation of long-chain acylcarnitine in the cytosolic and mitochondrial compartments. Treatment with 1-carnitine (30 or 100 mg/kg, i.v.) inhibited the mitochondrial accumulation of long-chain acylcarnitine. Free fatty acid (FFA) metabolism in the mitochondria differs from that in the cytosol. So, it is necessary to investigate the changes in FFA metabolism in both of these cellular compartments. Our results suggest that 1-carnitine has a protective effect on the ischemic heart by selectively reducing mitochondrial accumulation of long-chain acylcarnitine.

Effect of phenolic compounds on the polymerization of methyl methacrylate

The inhibitory effects of six phenolic compounds and two analogues on the polymerization of methyl methacrylate (MMA) by azobisisobutyronitrile (AIBM) were examined. Differential scanning calorimetry was used to determine the induction period (IP) and initial rate of polymerization (IRP). The IP values (minutes) decreased in the order: eugenol > thymol > hydroquinone > cresol > guaiacol > phenol >>> safrole > methol. The IRP values of all compounds tested ranged from 0.8 to 1.2 percent per minute, except for hydroquinone (0.2 percent per minute). Phenolic compounds inhibited the polymerization of MMA by scavenging radicals, and eugenol was the most potent inhibitor.

[Malignant histiocytosis associated with central neurological symptoms and cerebrospinal fluid involvement]

A 53-year-old woman was admitted with fever and general fatigue in December, 1988. A diagnosis of malignant histiocytosis (MH) was made based on her high level of LDH, thrombocytopenia, mild splenomegaly without systemic lymphadenopathy. There was also bone marrow infiltration large atypical cells and erythro-phagocytosis. VEPA therapy resulted in complete remission. Visual disturbance and left lagophthalmos were recognized in March 1990. These signs indicated central nervous system (CNS) relapse which disappeared after intrathecal methotrexate injection. The same symptoms and signs appeared after another, 5 months. Tumor cells were found not only in the central spinal fluid but also in bone marrow. CNS and bone marrow recurrence were treated with intrathecal methotrexate injection VEPA therapy and cranial irradiation. We diagnosed this case as MH, based on the clinical features which did not include systemic lymphadenopathy and laboratory findings although TcR-gamma rearrangement was observed in bone marrow cells. Only one case of CNS infiltration diagnosed when alive has previously been reported in Japan. We report here a very rare case in which by medical treatment CNS infiltrations was improved twice.

Hemolytic activity of a dental adhesive monomer (N-methacryloyloxy-5-aminosalicylic acid, MASA) and its interaction with phospholipid liposomes as studied by NMR and DSC

N-methacryloyloxy-5-aminosalicylic acid (MASA) has recently been used as an adhesive primer in restorative resin systems. To monitor the biological activity of MASA, we studied changes in NMR-chemical shifts (delta H) and the differential scanning calorimetry (DSC) phase transition temperature (Tm) of dipalmitoylphosphatidylcholine (DPPC)/MASA liposomes with or without the presence of albumin and collagen. The delta H and the Tm did not alter significantly and the interaction of MASA with DPPC was found to be small. Hemolytic activity of MASA was markedly smaller than that of the phosphate monomer (MDP) in bonding agents widely used. These findings suggest that using a MASA primer in resin systems has an acceptable biocompatibility for dentin-pulp, involving its adsorption and adhesion to hard tooth tissues.

A rapid and simple quantification of human apolipoprotein E-rich high-density lipoproteins in serum

A rapid and simple method for the quantitative determination of human serum apo E-rich high-density lipoproteins is described. A sample was divided into two parts; one part was mixed with an equal volume of 13% polyethylene glycol 6000, and the other part was mixed with a solution containing dextran sulfate, sodium phosphotungstate, and Mg2+, respectively. The mixed solutions were centrifuged (2000 g; 15 min). The supernate obtained by the former procedure contained both apo E-rich HDL and apo E-poor HDL, but that obtained by the latter procedure contained solely apo E-poor HDL. The serum apo E-rich HDL concentration in terms of apo E (E) and cholesterol (C), was given by the following equations: E = EP x 2, and C = (CP - CD) x 2, where EP and CP were the concentrations of apo E and cholesterol, respectively, in the supernate obtained with 13% polyethylene glycol, and CD was the concentration of cholesterol in the supernate obtained with the mixture solution of dextran sulfate, sodium phosphotungstate, and Mg2+. Normal serum apo E-rich HDL concentrations were 2.6 +/- 1.5 and 6.7 +/- 2.3 mg/dl (means +/- SD, n = 38) in terms of apo E and cholesterol, respectively. Apo E-rich HDL was increased strikingly in the sera from three patients with hepatobiliary diseases.

Apolipoproteins in rat cerebrospinal fluid: a comparison with plasma lipoprotein metabolism and effect of aging

Cerebrospinal fluid (CSF) apo E concentrations, determined by a sensitive sandwich ELISA, were 411.3 +/- 76.0 and 454.3 +/- 51.8 micrograms/dl (mean +/- S.D.) for young rats (8-12 weeks old, n = 7) and old rats (36-40 weeks old, n = 10), respectively. Age-related increase, which was conspicuous in serum apo E (21.2 +/- 2.4 vs 60.9 +/- 14.1 mg/dl for young and old rats, respectively), was not observed in CSF apo E. CSF apo A-I concentrations, determined by ELISA, were extremely low in the both groups (less than 10 micrograms/dl). Neither CSF apo A-I nor CSF apo E correlated to any of the plasma lipoprotein components, indicating the presence of largely independent lipoprotein metabolism in the rat central nervous system. Apo E is present in CSF in the form of apo E-rich HDL1 with particle sizes similar to those of plasma E-rich HDL1.

Spurious elevation of serum high-density lipoprotein cholesterol in patients with cholestatic liver diseases

Strikingly discrepant values were obtained by two commercial precipitating reagents for serum HDL cholesterol determination in three patients with cholestatic liver diseases (two patients with primary biliary cirrhosis and one patient with chronic hepatitis). An abnormal alpha 2-migrating lipoprotein (slow alpha-lipoprotein) was observed in agarose gel electrophoresis for each serum. The slow alpha-lipoprotein was partly recovered in the supernatant by precipitation with polyethylene glycol, and was completely precipitated with a polyanion-containing reagent, which well explains the discrepancy. The slow alpha-lipoprotein isolated from one of the cases is notable for (1) having an intermediate particle size between normal LDL and normal HDL, (2) containing apo E as the major apolipoprotein, and (3) being enriched with cholesterol (esterified and free) and phospholipid. Cholesterol accumulation was also found in another HDL subclass, alpha 1-migrating HDL. A severe impediment in the clearance of cholesterol-loaded HDL particles from plasma was implied. Electrophoresis of serum lipoproteins and/or the measurement of serum apo E concentrations are necessary to avoid an erroneous estimation of HDL cholesterol in patients with hepatobiliary diseases.

Changes in 1H-NMR chemical shifts of Bis-GMA and its related methacrylates induced by their interaction with phosphatidylcholine/cholesterol liposomes

To clarify the hemolytic mechanism of Bis-GMA and its related methacrylates, the interaction of five methacrylates (Bis-GMA, MMA, NPGDMA, TEGDMA, and UDMA) with DPPC/Cholesterol (CS) liposomes, as a model for erythrocyte membranes, was studied by 1H-NMR spectroscopy. Exogenous Bis-GMA partitioning into the DPPC/CS liposomes caused disappearances of its proton signals. With NPGDMA, its signals broadened markedly in DPPC/CS liposomes. UDMA partitioning caused changes in chemical shifts to a higher field, whereas MMA and TEGDMA partitioning did not cause any changes in chemical shifts. It was concluded from these observations that Bis-GMA has a stronger interaction with the DPPC/CS liposomes than the other methacrylates used. The high hemolytic activity of Bis-GMA reported previously seemed to be due to its migration into the lipid bilayer of phospholipids containing CS in erythrocyte membranes.

Hemolysis mechanism of dental adhesive monomer (methacryloyloxydecyl dihydrogen phosphate) using a phosphatidylcholine liposome system as a model for biomembranes

To clarify the mechanism of interaction of dental adhesive monomers with biological membranes at the molecular level, we studied the interaction of methacryloyloxydecyl dihydrogen phosphate (MDP) and methacrylic acid (MAA) with the dipalmitoylphosphatidylcholine (DPPC) liposome system using NMR and DSC. MDP-DPPC interaction became apparent through broadening of the DPPC phase transition as pH decreased, finally the enthalpy of MDP-DPPC (1:1 mol ratio) reduced to zero at pH 2.5. Proton chemical shifts of MDP enhanced shielding and proton signals due to the phosphatidylcholine polar group (O-CH2-CH2-N bond) of DPPC were observed. MAA-DPPC interaction was smaller than that of MDP-DPPC, even at low pH. It was concluded that the strong hemolytic activity of MDP may be due to its interaction with the phospholipid bilayers of erythrocyte membranes.

[Limitation of experimental infarct size by levo-carnitine chloride (LC-80), a new mitochondrial function-reactivating agent]

The effect of LC-80 on infarct size induced by 6 hr coronary occlusion was studied in anesthetized dogs. LC-80 at a dose of 100 mg/kg, i.v. was injected 5 min after coronary occlusion and then infused at a rate of 50 mg/kg, i.v./hr until the heart was excised. The two risk areas were determined both by injecting a fluorescent dye (Thioflavin S) into the left atrium (in vivo) and by perfusing the non-occluded coronary bed with Monastral Blue (in vitro). The infarct size was determined by topographically tracing the area of myocardium unstained by triphenyltetrazolium chloride. Four zones such as Zone 1 (normal tissue), Zone 2 (tissue characterized by collateral blood flow), Zone 3a (tissue developing necrosis), Zone 3b (necrotic tissue) were delimited . As a result, (1) LC-80 significantly diminished the incidence of ventricular arrhythmias. (2) LC-80 significantly inhibited the decrease in myocardial free carnitine level in Zone 2 and Zone 3b. (3) LC-80 significantly reduced the infarct size expressed as a percentage of the risk area and increased the size of Zone 2. (4) In the electron microscopic findings, LC-80 showed lesser morphological changes such as swollen mitochondria and intracellular and extracellular edema, especially in Zone 2. (5) LC-80 may be useful for inhibiting the evolution of myocardial ischemic cell death both by the protection of ischemic myocardium and presumably by the increase in the collateral blood flow.

Juvenile nephronophthisis diagnosed from glucosuria detected by urine screening at school

We describe the case of an 11-year-old girl in whom glucosuria detected by urine screening at school was the first clue to the diagnosis of juvenile nephronophthisis (JN). On admission, she showed renal failure with combined proximal and distal tubular defects and progressive deterioration of renal function. JN should be considered in children with glucosuria.

Changes in NMR chemical shifts of methacrylates induced by their interactions with the phospholipid and the phospholipid/cholesterol liposome system

The interaction of methyl methacrylate (MMA), ethylene dimethacrylate (EDMA) and triethyleneglycol dimethacrylate (TEGDMA), which are widely used in dentistry, with the dipalmitoyl phosphatidylcholine (DPPC) and the DPPC/cholesterol (CS) liposome system was studied by 1H and 13C nuclear magnetic resonance spectroscopy (NMR). EDMA and TEGDMA have a larger interaction with the DPPC liposome system compared to MMA, resulting in changes in chemical shifts. The 13C chemical shift differences of C = C-C-O were larger than those of other carbon portions in methacrylate, indicating that double bonds interact predominantly with DPPC liposomes due to the hydrophobicity of methacrylates. At 37 degrees C, 1H signals from TEGDMA appeared in the DPPC/CS/TEGDMA liposome system, while signals due to H2C = C-C-OCH2CH2 did not appear in the DPPC/TEGDMA liposome system.

Effects of L-carnitine and palmitoylcarnitine on membrane fluidity of human erythrocytes

Amphiphilic compounds such as long-chain acyl carnitine accumulate in ischemic myocardium and potentially contribute to the myocardial damage, and the role of carnitine in protecting the heart against ischemic damage is interesting. It has been reported that palmitoylcarnitine causes alterations in the membrane molecular dynamics, so this study was designed to investigate whether L-carnitine had a stabilizing effect of membrane fluidity using the spin-label technique. Human erythrocytes were spin-labeled with 5-doxylstearic acids, and membrane fluidity was quantified by measuring the change in the order parameter S. The administration of palmitoylcarnitine (100 microM) altered the membrane fluidity of erythrocytes and caused significant morphological changes. L-carnitine (2mM) decreased the alteration of the fluidity of erythrocytes incubated with palmitoylcarnitine (100 microM), and improved the morphological changes in erythrocytes. These results show that L-carnitine has a stabilizing effect of membrane fluidity as a result of interaction with the palmitoylcarnitine which has a detergent effect.

[The correlation of serum IgE and IgE-RAST of mite, egg white, milk, soybean, rice and wheat: a study by analysis of regression curves]

The correlation of variation in serum IgE and IgE-RAST in 364 cases of patients with atopic dermatitis (AD) aged 4 months to 78 years was analysed by comparison with the scatter diagram and fifth dimension regression curve representing the serum IgE and IgE-RAST scores of mite, egg white, milk, soybean, wheat and rice. The antigens indicating a high IgE-RAST score varied according to age. They were egg white and milk in infancy and mite from one to fifteen years of age. Rice and wheat came later. A high value of serum IgE with AD was seen to depend on the production of specific mite IgE antibody and to be influenced by each specific IgE antibody production, which varied according to age. It seemed that egg white and milk were initiators of AD and mite acted as a promotor. Rice and wheat were accelerators in patients with adult type AD. It was confirmed that, for AD patients of all ages, improvement of the environmental antigens and diet therapy was necessary.

Nuclear magnetic resonance spectroscopic studies of interaction of bis-GMA analogues with phosphatidylcholine liposomes as a model for biomembranes

The interaction of bis-GMA analogues with dipalmitoylphosphatidylcholine liposomes was studied by 1H and 13C nuclear magnetic resonance spectroscopy. It was found that bis-GMA analogues did not diffuse from liposomes once they were incorporated into the lipid bilayers of dipalmitoylphosphatidylcholine. The mobility of iso-bis-GMA was strongly disturbed by dipalmitoylphosphatidylcholine. The large changes in nuclear magnetic resonance spectra of iso-bis-GMA indicated that the interaction of iso-bis-GMA with dipalmitylphosphatidylcholine was larger than that of bis-GMA. This seems to be due to the chemical structure of iso-bis-GMA with the primary hydroxyl group.

[Studies on the beneficial effect of levocarnitine chloride (LC-80) on organic acidemias, especially propionic acidemia and methylmalonic acidemia]

The beneficial effect of LC-80 in the therapy for organic acidemias, especially propionic acidemia and methylmalonic acidemia, was compared with those of its optical isomers, d-carnitine chloride (d-isomer) and dl-carnitine chloride (dl-isomer) in rat liver mitochondria. LC-80 at concentrations of 5 and 10 mM did not inhibit the mitochondrial function, while the d-isomer at a concentration of 5 mM significantly reduced the respiratory control ratio (RCR) of mitochondria. In addition, the dl-isomer at concentrations of 10 and 20 mM also significantly reduced RCR in a concentration-dependent manner. Thus, it seems likely that the d-isomer inhibits the mitochondrial function. On the other hand, the inhibition of mitochondrial function induced by a preincubation with propionate (4.76 mM) was significantly reversed by LC-80 (5 and 10 mM) in a concentration-dependent manner, while the d-isomer (5 mM) had no effect on the inhibitory effect of propionate. Moreover, although the dl-isomer (10 and 20 mM) significantly reversed the inhibitory effect of propionate as compared with the d-isomer, its effect was significantly weaker as compared with the effect of LC-80. The substrate specificity of rat liver mitochondrial carnitine acetyltransferase (CAT) was more potent with propionyl CoA than with acetyl CoA. Kinetic studies indicate that the d-isomer is a competitive inhibitor of CAT. These results suggest that LC-80 is useful in the clinical treatment of organic acidemias, whereas the d-isomer has a harmful effect in clinical application.

[Effects of levocarnitine chloride (LC-80) on the cardiovascular system]

The cardiovascular effects of levocarnitine chloride (LC-80) were investigated in in vitro and in vivo experiments, and the following results were obtained: (1) In isolated rabbit cardiac muscle preparations, LC-80 at the high concentration of 10(-2) M had little influence on the atrial rate of spontaneously beating right atria, while it caused a gradual increase in the contractile tension of both spontaneously beating right atria and electrically driven papillary muscle that reached a maximum level after 10 min of administration and lasted for 20-30 min. However, the LC-80-induced positive inotropic effect may be negligible in whole animal experiments or clinical trials, since it was elicited only after the administration of LC-80 in an extremely large dose. Furthermore, LC-80 in a high concentration (10(-2) M) had no influence on the isoproterenol-induced positive inotropic effect in electrically driven papillary muscles. (2) LC-80 in high concentrations of 10(-3)-10(-2) M did not affect the high K+-induced contraction in isolated canine left circumflex coronary artery and saphenous vein. (3) In anesthetized dogs, intraarterial injection of LC-80 in high doses of up to 10 mg did not change the blood flow of coronary, femoral, renal, mesenteric or vertebral arteries and on the adenosine-induced vasodilator action. (4) In anesthetized dogs, intravenous injection of LC-80 in doses of 100-300 mg/kg did not modify the blood pressure responses induced by norepinephrine, acetylcholine, carotid occlusion and vagal stimulation. These results suggest that the cardiovascular effects of LC-80 are extremely mild or negligible. Therefore, LC-80 may be a drug having a new pharmacological feature in its mechanism which enables it to exert a beneficial effect in the treatment of ischemic heart disease, being different from the commonly used antianginal drugs.